(a) Field of the Invention
The present invention relates to a liquid crystal display.
(b) Description of the Related Art
Generally, a liquid crystal display has two substrates with electrodes, and a liquid crystal layer sandwiched between the two substrates. Voltages are applied to the electrodes so that the liquid crystal molecules in the liquid crystal layer are reoriented to thereby control the light transmission.
The liquid crystal display has a plurality of pixels with pixel electrodes and color filters of red, green and blue. The pixels are driven by way of signals applied through the wiring lines. The wiring lines include scanning signal lines or gate lines for carrying scanning signals, and picture signal lines or data lines for carrying the picture signals. Thin film transistors are formed at the respective pixels while each being connected to one gate line and one data line. The picture signals applied to the pixel electrodes are controlled by way of the thin film transistors.
There are several types of arrangement with the color filters of red, green and blue. Among them are a stripe type where the color filters of the same color are arranged at the respective pixel columns, a mosaic type where the color filters of red, green and blue are sequentially arranged in the pixel row and column directions, and a delta type where the pixels are zigzag-alternated in the pixel column direction, and the color filters of red, green and blue are sequentially arranged at the pixels. In the case of the delta type, the three unit pixels with the color filters of red, green and blue are operated as one dot, and this makes it easy to express a circle or a diagonal line.
The ClairVoyante Laboratories have proposed a pixel arrangement structure called the “PenTile Matrix™,” which has a high resolution expression capacity advantageous in displaying pictures while being involved minimized design cost. In such a pixel arrangement structure, the unit pixel of blue is common to two dots, and the neighboring blue pixels receive the data signals from one data driving IC while being driven by two different gate driving ICs. With the use of the PenTile Matrix pixel structure, the resolution of the UXGA level can be realized by way of a display device of the SVGA level. Furthermore, the number of low-cost gate driving ICs is increased, but the number of high-cost data driving ICs is decreased. This minimizes the design cost for the display device.
However, in the above-structured liquid crystal display, the unit pixels of blue are arranged in the shape of a diamond and correspondingly, the signal lines for carrying the data signals are bent. Consequently, only the data signal line for transmitting the relevant signals to the blue pixels is elongated so that delay in the signal transmission is made with respect to the data signals for the blue pixels, and the display characteristic becomes to be non-uniform. Therefore, there is a limit in applying the Pentile Matrix pixel arrangement structure to the large-sized liquid crystal display. Furthermore, the red or green pixels are provided around the blue pixel per the two pixel columns, and the blue pixel differs in size from the red or green pixel. This makes it very difficult to form storage capacity required for the liquid crystal display.
Meanwhile, the data signal lines for transmitting data signals to the red or green pixels, or two gate signal lines are placed close to each other so that the wiring lines are liable to be short-circuited while reducing the production yield and deteriorating the display characteristic. Furthermore, as the neighboring blue pixels are driven by one driving IC, the data driving IC should be provided at both sides of the display region and this induces enlargement of the display device. In addition, with this structure, it becomes difficult to form repair lines at the periphery of the display region. The repair lines are to prevent the wiring lines from being cut or short-circuited.
In order to prevent the liquid crystal from being deteriorated, the inverse-driving technique should be used to drive the display device. However, in this case, polarity is non-uniformly made with respect to the red, green and blue pixels while generating flicker as well as brightness difference among the pixel columns. This deteriorates the picture quality of the resulting display device.
Meanwhile, in the liquid crystal display with the Pentile Matrix pixel arrangement structure, the rendering technique should be used in driving the pixels to display the picture images at high resolution.